Chusetts



Patentedv Aug. 4. 1896.

lllll 11|? CIRCUIT BRBAKBR.

W. B. TCB-EY 8v H. W.. SMITH.

IH Illll (No Model.)

circuit-breakers more especially designed for UNITED STATES PATENTOFFICE.`

VILLIAM B. TOBEY AND HERBERT NV. SMITH, OF PITTSFIELD, MASSA- CHUSETTS.

CIRCUIT-BREAKER.

SPECIFICATION forming part of Letters Patent No. 565,244, dated August4, 1896.

Serial No. 560,734. (No model.)

T0 all whom it may concern.:

Beit known that we, WILLIAM B. TOBEY and HERBERT XV. SMITH, citizens ofthe United States, residing at Pittsfield, in the county of Berkshireand State of Massachusetts, have invented certain new and usefulImprovements in Circuit-Breakers, of which the following is aspecification, reference being had to the drawings accompanying andforming a part of the same.

The invention subject of our present application is an improvement inswitches or use with circuits carrying powerful currents and constructedwith the object of preventing the formation or destructive action of anarc between the terminals at the time of their separation in theoperation of interrupting the circuit of which they form a part.

ln principle of construction and mode of operation the improvement isnot broadly novel-that is to say, the operation of the device which iseffective for the prevention of an arc depends upon the principle ofinterposing between the terminal points at the instant of theirseparation a body to intercept or to receive upon itself the arc, andthus prevent the deterioration of the contact plates or portions of theswitch. IVe have, however, devised a special form of switch for thispurpose, which acts also to blow out the arc and to more effectivelyshut off or isolate the terminal contacts after separation. Ourimprovement resides and consists in the device by which we accomplishthis result.

In the accompanying drawings, Figure l is a view in side elevation withparts in section of the switch in the general form in which we constructit for practical use on high-voltage circuits. Fig. 2 is a perspectiveview of a typical form of the arc-preventing mechanism which we havedevised. Fig. 3 is a cross-section of the device of Fig. 2.

The means for preventing the formation of an arc exempliiied in Fig. 2may be applied to various forms of switch, but that shown in Fig. l isselected for the reason that it embodies certain other improvements indetails of construction which contribute to the efficacy of the deviceas a whole. The said device comprises an insulating-base A, on which ismounted a standard B, to which the switch arm or lever C, having ahandle D, is pivoted. The two terminals to be bridged by the switch-armare also mounted on the base A and connected with the circuit-wires inany ordinary and proper manner.

The arm or lever C is composed mainly of insulating material or so thatno exposed metallic portion except the terminals is in electricalconnection with any part of the circuit. The terminal plates F. E extenddownwardly from the lever, in which they are set and connected by ametallic bridgepiece F, embedded in the material of said lever.

The stationary terminals are, furthermore, inclosed in insulating-boxesG, having openings or slots in their tops, through which the blades Eenter to engage with the terminals.

Fig. 2 illustrates the plan upon which these latter are constructed andwhich may be described as follows: H H are two metal plates (one wouldof course suffice, but two are preferable) in permanent connection withthe circuit-wires in or under the insulating-base. These plates areinclosed by two hinged and spring-actuated or spring-supported shuttersK K, which in the present case are shown as secured to the spring-platesL L, secured to the base A.

The shutters may be either of insulating or conducting material, but forhigh-voltage circuits are of insulating material and of somewhat greaterdimensions than the contactplates, so as, when pressed together by theaction of the springs L, to completely inclose and shut in the saidplates. They may also be provided, respectively, with a tongue andgroove above the contact-plates, as shown at M, so that when closed aportion of one shutter bridges the line of junction of the two plates.

When the plate E is pressed down, it enters the groove formed by thebeveled or rounded edges of the shutters and forces the latter apart. Asit passes downward it engages with the two contact-plates and completesthe circuit. Vhen it is withdrawn, by raising the lever the shuttersclose together with considerable force, and so rapidly as to effectuallyIOO extinguish any arc that may tend to form between the contact-platesand the plate or blade E. Thus the plates are always preserved clean andbright and are not impaired by continued use.

Y/Vhen low-voltage currents are used, as in railroad systems, theshutters may be of metal or carbon and may be in electrical conneetionWith the terminal plates. The arc which under such circumstances formsand which is apt to fuse the terminals more or less and leave smallglobules of molten metal on the same affects the shutters only and notthe contact plates or surfaces, which latter, being tightly closedtogether the instant the blade E leaves them, are preserved intact andbright.

It will be understood, of course, that the shutters may be moved over astationary blade, and that the details of construction in this and otherrespects may be varied Without departure from the invention.

1.. The combination with the spring-actuated and normally-closedshutters of insulating material and the contact-plates embedded in theircontiguous surfaces, of a blade or plate acting as a Wedge for forcingapart the shutters When brought into engagement with the contact-plates,said shutters being adapted to close by the instantaneous reaction ofthe springs When the blade is Withdrawn, as set forth.

2. The combination with the spring-actuated shutters having flatsurfaces and intermeshing or overlapping parts held normally in contactby the springs, and contact-plates embedded in the contiguous flatsurfaces, of a plate or blade acting as a Wedge for forcing apart theshutters when brought into engagement With the contact-plates, as setforth.

The combination with the insulatingbase and one or more pairs ofcontact-plates socured to and embedded in the surfaces ofoppositely-spring-actuated and normallyclosed shutters mounted on thebase and inclosed in insulated boxes with openings therein, oi' a levercarrying one or more plates or blades adapted to enter the openings inthe boxes and force apart the shutters to engage with the contact-platescarried thereby, as set forth.

In testimony whereof We have hereunto set our hands this 20th day ofAugust, 1895.

XVM. B. TOBEY. HERBERT XV. SMITH. Vitnesses:

JoHN F. KELLY, C. C. CHESNEY.

